2 * link.c --- create links in a ext2fs directory
4 * Copyright (C) 1993, 1994 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
29 unsigned int blocksize;
31 struct ext2_super_block *sb;
34 static int link_proc(struct ext2_dir_entry *dirent,
40 struct link_struct *ls = (struct link_struct *) priv_data;
41 struct ext2_dir_entry *next;
42 unsigned int rec_len, min_rec_len, curr_rec_len;
45 struct ext2_dir_entry_tail *t;
50 rec_len = EXT2_DIR_REC_LEN(ls->namelen);
52 ls->err = ext2fs_get_rec_len(ls->fs, dirent, &curr_rec_len);
56 if (EXT2_HAS_RO_COMPAT_FEATURE(ls->fs->super,
57 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
58 csum_size = sizeof(struct ext2_dir_entry_tail);
60 * See if the following directory entry (if any) is unused;
61 * if so, absorb it into this one.
63 next = (struct ext2_dir_entry *) (buf + offset + curr_rec_len);
64 if ((offset + (int) curr_rec_len < blocksize - (8 + csum_size)) &&
66 (offset + (int) curr_rec_len + (int) next->rec_len <= blocksize)) {
67 curr_rec_len += next->rec_len;
68 ls->err = ext2fs_set_rec_len(ls->fs, curr_rec_len, dirent);
75 * Since ext2fs_link blows away htree data, we need to be
76 * careful -- if metadata_csum is enabled and we're passed in
77 * a dirent that contains htree data, we need to create the
78 * fake entry at the end of the block that hides the checksum.
81 /* De-convert a dx_node block */
83 curr_rec_len == ls->fs->blocksize &&
85 curr_rec_len -= csum_size;
86 ls->err = ext2fs_set_rec_len(ls->fs, curr_rec_len, dirent);
89 t = EXT2_DIRENT_TAIL(buf, ls->fs->blocksize);
90 ext2fs_initialize_dirent_tail(ls->fs, t);
94 /* De-convert a dx_root block */
96 curr_rec_len == ls->fs->blocksize - EXT2_DIR_REC_LEN(1) &&
97 offset == EXT2_DIR_REC_LEN(1) &&
98 dirent->name[0] == '.' && dirent->name[1] == '.') {
99 curr_rec_len -= csum_size;
100 ls->err = ext2fs_set_rec_len(ls->fs, curr_rec_len, dirent);
103 t = EXT2_DIRENT_TAIL(buf, ls->fs->blocksize);
104 ext2fs_initialize_dirent_tail(ls->fs, t);
105 ret = DIRENT_CHANGED;
109 * If the directory entry is used, see if we can split the
110 * directory entry to make room for the new name. If so,
111 * truncate it and return.
114 min_rec_len = EXT2_DIR_REC_LEN(ext2fs_dirent_name_len(dirent));
115 if (curr_rec_len < (min_rec_len + rec_len))
117 rec_len = curr_rec_len - min_rec_len;
118 ls->err = ext2fs_set_rec_len(ls->fs, min_rec_len, dirent);
121 next = (struct ext2_dir_entry *) (buf + offset +
124 ext2fs_dirent_set_name_len(next, 0);
125 ext2fs_dirent_set_file_type(next, 0);
126 ls->err = ext2fs_set_rec_len(ls->fs, rec_len, next);
129 return DIRENT_CHANGED;
133 * If we get this far, then the directory entry is not used.
134 * See if we can fit the request entry in. If so, do it.
136 if (curr_rec_len < rec_len)
138 dirent->inode = ls->inode;
139 ext2fs_dirent_set_name_len(dirent, ls->namelen);
140 strncpy(dirent->name, ls->name, ls->namelen);
141 if (ls->sb->s_feature_incompat & EXT2_FEATURE_INCOMPAT_FILETYPE)
142 ext2fs_dirent_set_file_type(dirent, ls->flags & 0x7);
145 return DIRENT_ABORT|DIRENT_CHANGED;
149 * Note: the low 3 bits of the flags field are used as the directory
155 errcode_t ext2fs_link(ext2_filsys fs, ext2_ino_t dir, const char *name,
156 ext2_ino_t ino, int flags)
159 struct link_struct ls;
160 struct ext2_inode inode;
162 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
164 if (!(fs->flags & EXT2_FLAG_RW))
165 return EXT2_ET_RO_FILSYS;
169 ls.namelen = name ? strlen(name) : 0;
174 ls.blocksize = fs->blocksize;
177 retval = ext2fs_dir_iterate(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY,
185 return EXT2_ET_DIR_NO_SPACE;
187 if ((retval = ext2fs_read_inode(fs, dir, &inode)) != 0)
191 * If this function changes to preserve the htree, remove the
192 * two hunks in link_proc that shove checksum tails into the
193 * former dx_root/dx_node blocks.
195 if (inode.i_flags & EXT2_INDEX_FL) {
196 inode.i_flags &= ~EXT2_INDEX_FL;
197 if ((retval = ext2fs_write_inode(fs, dir, &inode)) != 0)